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Centritherm® Evaporator Short Path Distillation

Superior distillation

Short-path or molecular distillation applications in the edible oil, polymer, chemical, flavour chemical, essential oil and similar industries typically require high temperatures and vacuums, which are not possible in traditional evaporation units. At Flavourtech we have specifically developed the RM-SP series of Centritherm® evaporators, which are designed with a unique internal condensing system to meet the requirements of short-path distillation.

Applications for this revolutionary technology include:

  • Separation and purification of Omega fatty acids
  • Removal of residual monomers from polymeric suspensions
  • Separation and purification of essential oils
  • Separation and purification of squalene

Benefits

woman applying perfume on her wrist

Very thin film

The Centritherm evaporator for short path distillation uses centrifugal force to create a thin film of product on a rotating conical heated surface. The film thickness is fractions of a millimetre, enabling a rapid transfer of heat energy and hence effective evaporation of the volatile material. The centrifugally induced film is much thinner and more evenly distributed than that in traditional wiped film evaporator units.

Short residence time

The centrifugal force evenly distributes a thin film, resulting in residence times on the heating surface of less than one second. This is substantially shorter than other forms of thin film evaporators, which have residence times of 15 to 20 seconds.

Ripe orange citrus grove

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Low thermal impact

Due to the very short contact time with the heating surface the thermal impact is minimal. Even when working at the relatively high temperatures required to separate compounds that have high boiling points, the impact on the final product is minimised.

Suitable for short path and molecular distillation

The unique design of these units makes them suitable for short path distillation as the internal condenser is designed to reduce the distance between the evaporating and condensing surfaces to a few centimetres.

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Compact, modular and flexible unit

The units are constructed as compact modular systems, complete with pumps, pipe work, electrical and control systems. The modular design allows for easy installation of the units in parallel or in series to suit specific applications, particularly where multiple separation steps are required to isolate a particular compound.

The unit can be delivered with both an internal and an external condenser, which are simple and quick to install and remove, allowing operation at a broad range of vacuums. This makes the RM-SP series particularly suitable for small production or R&D facilities where multiple products are required to be processed. The units also offer a choice of construction materials (including Hastelloy), seal designs and heating media.

Case Study

Hiap Huat Chemicals

Hiap Huat Chemicals is a Malaysian based company that has a strong focus on being environmentally conscious and on conserving natural resources. Their mission is to create long lasting partnerships by providing their customers complete recycling services.

Their services include: recycling of waste motor oil, oil drums, maintenance and service of facilities and treatment of contaminated soil. Hiap Huat Chemicals have four factories for the processing and recycling of waste materials using the latest technology. One of these technologies is the Centritherm Short Path evaporator. This is assisting Hiap Huat Chemicals clean up and recycle used motor and hydraulic oil thereby helping the environment in preventing this waste oil going to landfill.

Read More

How it works

The RM series Centritherm evaporator consists of a single spinning cone, which is fixed to a rotating base, located within a static housing which includes a removable outer cover.

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Product is fed onto the inner surface of the spinning cone through a feed tube and nozzle. Centrifugal force quickly distributes the liquid evenly over the heating surface in a very thin film, approximately 0.1 to 1.0 mm depending on the product viscosity, rotational speed and flow rate. The concentrate is then picked up by a stationary paring tube and pumped out of the unit.

The heat required to evaporate the boiling compounds is supplied to the product film through the thin, spinning cone wall. The heating medium, such as steam or hot oil, is located between the spinning cone and the outer cover.

The vaporised compounds leave the thin film of product and, when an internal condenser is used, are almost immediately condensed on the outer surface of condenser cooling tubes. A cooling medium is circulated within these tubes and the distillate that forms falls onto a collection plate and flows out of the evaporation chamber to a distillate pump.

The RM series Centritherm thin film evaporator units are available with both external (EC) or internal condensing systems (SP).

Models

High vacuum Centritherm evaporator, model CT1-40RM

High vacuum Centritherm evaporator, model CT1-40RM

An example of a typical Short Path distillation installation is a two stage system where the first stage operates as a thin film evaporator at a moderate vacuum (>1 mbar) with an external condenser. This stage is used to preheat the product, remove dissolved or entrained gas, excess solvent or other volatile compounds so that the second stage can reach the high vacuums required.

The second stage, complete with internal condenser, operates as a short path or molecular distillation unit at high vacuums (1 mbar to 0.001 mbar) to recover a

High vacuum Short Path Centritherm evaporator, model CT1-130RMSP-2

High vacuum Short Path Centritherm evaporator,
model CT1-130RMSP-2

distillate of low boiling point compounds.

Suitable applications include the removal of pesticides from edible oils and waxes, purifying essential oils and low temperature refining of edible oils.

Multiple stage Short Path systems are also available for applications requiring several stages or passes to achieve the desired degree of separation. For example, for the recovery of Omega 3 fatty acid esters from esterified fish oil, this system operates as such:

  • The first stage removes dissolved gases, excess alcohol and other volatile compounds left after the esterification reaction;
  • The second evaporates the bulk of the shorter chain fatty acid esters; and
  • The third (and sometimes fourth) stage processes the residue from the second stage producing a concentrated distillate of the omega 3 fatty acid esters.

The below table outlines the available models for the RM series Centritherm evaporator. All units may be used for Short Path distillation when an internal condenser and high vacuum pump are selected. 

 CT1-09RMCT1-40RMCT1-130RM
ConfigurationThin Film | Short PathThin Film | Short PathThin Film | Short Path
Cone speed (RPM)1400 to 1800600 to 800300 to 500
Cone diameter
(appx. metres)
0.30.61.3
Max saturated
steam temp. (°C)
143143120
Max heating*
oil temp. (°C)
180180180
CondenserExternal | InternalExternal | InternalExternal | Internal
Nominal feed rate**
(kg/hr)
5 to 6525 to 20075 to 600
* Standard design, special designs possible
** Capacity varies depending on the product characteristics and evaporation ratios required. Contact Flavourtech for specific application data.

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